Editing BSP Visual Mesh - Entity Won't Inject - Possible?

Hey, I extracted dune's visual meshes (from BSP) in entity, with hopes to remodel the tower on dune. I know I cannot change the collision, so i only made subtle changes to the model. Now I tried to inject them back, so I went to inject BSP visual meshes, and selected the correct folder. Now, at this point, I receive an error saying that dune[16] could not be found - the thing is that dune[16] was never extracted in the first place.

Is visual mesh editing possible? Am I doing it the most efficient way? Why can't I inject the meshes?

you can change the collision of the tower you would have to extract the BSP collision and open up the .mtl in notepad than open the collision model find a vertexs coordinantes than find it in notepad and drop it down to where you want